/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlineChatInterface.h
Delegate used when creating a new chat room
typedef TMulticastDelegate_FourParams< void, const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) &, const [FChatRoomId](API\Plugins\OnlineSubsystem\Interfaces\FChatRoomId) &, bool, const [FString](API\Runtime\Core\Containers\FString) & > FOnChatRoomCreated